[Bug]: TypeInitializationException with ReactiveUI/Autofac/Avalonia on newer Splat.Core versions

[ArcanoxDragon]

Describe the bug 🐞

I just updated all NuGet packages in my Avalonia desktop application, and I am getting a TypeLoadException in BuildAvaloniaApp now from ReactiveUI:

System.TypeInitializationException: 'The type initializer for 'ReactiveUI.RxApp' threw an exception.'
Inner Exception
TypeLoadException: Could not load type 'Splat.ExceptionMixins' from assembly 'Splat.Core, Version=19.2.0.0, Culture=neutral, PublicKeyToken=null'.

This is occurring on my call to InitializeReactiveUI:

// In Program.cs, BuildAvaloniaApp
var builder = new ContainerBuilder(); // Autofac.ContainerBuilder
var resolver = builder.UseAutofacDependencyResolver(); // From Splat.Autofac.SplatAutofacExtensions

// Crashes here:
resolver.InitializeReactiveUI(); // From ReactiveUI.DependencyResolverMixins

I can fix this by manually installing an older version of Splat.Autofac - versions up to and including 17.2.1 work, but 18.1.1 and up are broken. The version of Splat.Core mentioned in the exception is different depending on what version is installed - 18.1.1 produces from assembly 'Splat.Core, Version=18.1.0.0, for instance. These all seem to correspond with assembly versions that do not have a matching package version on NuGet.

I'm not sure if this is the fault of ReactiveUI or Splat, but given that the stack trace is coming from ReactiveUI, I decided to start here.

Step to reproduce

1. Clone the reproduction repo and build.
2. Ensure the application launches.
3. Update project's Splat.Autofac dependency to any newer version, such as the latest 19.2.1.
4. Attempt to launch the application again, and observe that it crashes early during initialization.

Reproduction repository

https://github.com/ArcanoxDragon/ReactiveUiSplatRepro

Expected behavior

Using the latest versions of ReactiveUI/Splat/Autofac together should not cause exceptions on application launch. ReactiveUI should not attempt to load types from an assembly version that does not exist on NuGet.

Screenshots 🖼️

No response

IDE

Visual Studio 2022

Operating system

Windows 10 x64

Version

22H2

Device

No response

ReactiveUI Version

22.2.1

Additional information ℹ️

No response

[database64128]

Same here with WPF.

[glennawatson]

@database64128 you'll need to use the beta if you want to use Splat 19, otherwise stick with 18 until the full release which will be in the next couple weeks.

[glennawatson]

Stick with Splat 18 until the beta release son of ReactiveUI.Avalonia and full release in March.

[mimeister]

This also happens with version 18 (WPF). I had to go back to Splat 17.